The invention relates to composite materials. More particularly, the invention relates to composite materials comprising a noble metal film deposited on a low work function support. Even more particularly, the invention relates to composite materials comprising a noble metal film deposited on a metal hexaboride support.
Noble metals, such as gold, platinum, and the like, have high electrical conductivity, chemical stability, and superior catalytic properties. Due to these properties, they are used in a variety of applications, including electrical contacts, chemical catalysts, and fuel cell electrodes.
The cost of such noble metals, however, is considered to be prohibitive, and considerable effort has been made to minimize the amount of such metals used in different applications while maximizing their beneficial effects. To this end, thin films of noble metals are frequently deposited on a relatively inert support, such as, for example, a ceramic or carbon. Even here, the effectiveness of the noble metals is limited by their tendency to ball up rather than wet the surface of the support. Moreover, thin films of such noble metals are usually deposited by physical vapor deposition methods, which in themselves add multiple levels of complexity.
Presently, there are no methods for depositing noble metals on support materials that have low work functions at room temperature or in open air. Therefore, what is needed is a low temperature method of depositing thin films of noble metals on a support having a low work function. What is also needed is a composite material comprising a thin film of such noble metals.